Background: Trimethylamine (TMA) is a nitrogenous base aliphatic organic compound
accounting for the odor of rotten fish and it is used as an indicator for analyzing the quality of fish
Introduction: Extraction procedures and analytical methods including colorimetric and Gas-
Chromatography (GC) can quantify the TMA contents of fish products after pre-treatment with basic
solutions. However, the extraction procedure and analytical methods for acid-treated samples are not
known, despite the majority of fish products being preserved using acid preservatives.
Methods: The methodologies used included solid-phase micro-extraction of TMA followed by its
quantification by a GC-based analytical method. An analysis of response surface methodology was
also conducted to verify the optimum conditions for TMA detection in acid-treated liquid samples
affected by factors including trapping time, temperature, and stirring speed.
Results: The results obtained from this study showed that the optimum conditions for the best yield
of TMA extraction are 20 min of trapping, emission at 55°C, and stirring at 400 rpm. The validation
of the developed method was carried out using rotten fish after acid treatment. Acid treatment decreased
TMA by up to 73.01%, however, when adding NaOH solution of the same volume to the
samples, TMA increased similar to the control group.
Conclusion: Here, we report a simple, sensitive, and rapid extraction procedure. A GC-based analytical
method was developed for the analysis of TMA from the acid-treated sample. The developed extraction
procedure and analytical methods were optimized and validated, which could be helpful for
the extraction of TMA without damaging the sample.